The invention relates to a head unit for a stop holder for stabilizing a drilling machine during the placement and/or machining of a component hole, to a stop holder and to a method for stabilizing a drilling machine during the placement and/or machining of a component hole in at least one component that is arranged so as to be adjacent to, or in sections overlapping with, some other component.
Conventional head units of stop holders or stop countersinks for stabilizing a drilling machine during the placement and/or machining of a component hole comprise a tubular round body which by way of a rear assembly section can be detachably attached to the stop holder, an axial tool space for leading-through a tool chucked in the stop holder, and a front rest section for resting on the components. During the placement and/or machining of the component hole the drilling machine is supported, by way of an annular contact surface of the rest section, on the respective component or is pressed against said component. However, supporting the head unit requires a minimal free space on the component in the region of the component hole to be formed or to be machined. If the free space provided by the component around the component hole is not sufficient, the head unit cannot be used or cannot be placed onto the component in a tilt-proof manner. For example, if two components are arranged with height displacement relative to each other, and if a depression is to be made in a hole of the lower component, then the hole needs to be situated a minimum distance from the edge of the upper component in order to ensure a tilt-proof footing of the head unit.